/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.startup;

import org.apache.catalina.*;
import org.apache.tomcat.util.res.StringManager;

import java.io.File;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.regex.Pattern;

/**
 * Startup event listener for a <b>Host</b> that configures Contexts (web
 * applications) for all defined "users" who have a web application in a
 * directory with the specified name in their home directories.  The context
 * path of each deployed application will be set to <code>~xxxxx</code>, where
 * xxxxx is the username of the owning user for that web application
 *
 * @author Craig R. McClanahan
 */
public final class UserConfig
		implements LifecycleListener {

	private static final org.apache.juli.logging.Log log =
			org.apache.juli.logging.LogFactory.getLog(UserConfig.class);


	// ----------------------------------------------------- Instance Variables
	/**
	 * The string resources for this package.
	 */
	private static final StringManager sm =
			StringManager.getManager(Constants.Package);
	/**
	 * A regular expression defining user who deployment is allowed.
	 */
	Pattern allow = null;
	/**
	 * A regular expression defining user who deployment is denied.
	 */
	Pattern deny = null;
	/**
	 * The Java class name of the Context configuration class we should use.
	 */
	private String configClass = "org.apache.catalina.startup.ContextConfig";
	/**
	 * The Java class name of the Context implementation we should use.
	 */
	private String contextClass = "org.apache.catalina.core.StandardContext";
	/**
	 * The directory name to be searched for within each user home directory.
	 */
	private String directoryName = "public_html";
	/**
	 * The base directory containing user home directories.
	 */
	private String homeBase = null;
	/**
	 * The Host we are associated with.
	 */
	private Host host = null;
	/**
	 * The Java class name of the user database class we should use.
	 */
	private String userClass =
			"org.apache.catalina.startup.PasswdUserDatabase";

	// ------------------------------------------------------------- Properties

	/**
	 * Return the Context configuration class name.
	 */
	public String getConfigClass() {

		return (this.configClass);

	}

	/**
	 * Set the Context configuration class name.
	 *
	 * @param configClass The new Context configuration class name.
	 */
	public void setConfigClass(String configClass) {

		this.configClass = configClass;

	}

	/**
	 * Return the Context implementation class name.
	 */
	public String getContextClass() {

		return (this.contextClass);

	}

	/**
	 * Set the Context implementation class name.
	 *
	 * @param contextClass The new Context implementation class name.
	 */
	public void setContextClass(String contextClass) {

		this.contextClass = contextClass;

	}

	/**
	 * Return the directory name for user web applications.
	 */
	public String getDirectoryName() {

		return (this.directoryName);

	}

	/**
	 * Set the directory name for user web applications.
	 *
	 * @param directoryName The new directory name
	 */
	public void setDirectoryName(String directoryName) {

		this.directoryName = directoryName;

	}

	/**
	 * Return the base directory containing user home directories.
	 */
	public String getHomeBase() {

		return (this.homeBase);

	}

	/**
	 * Set the base directory containing user home directories.
	 *
	 * @param homeBase The new base directory
	 */
	public void setHomeBase(String homeBase) {

		this.homeBase = homeBase;

	}

	/**
	 * Return the user database class name for this component.
	 */
	public String getUserClass() {

		return (this.userClass);

	}

	/**
	 * Set the user database class name for this component.
	 */
	public void setUserClass(String userClass) {

		this.userClass = userClass;

	}

	/**
	 * Return the regular expression used to test for user who deployment is allowed.
	 */
	public String getAllow() {
		if (allow == null) return null;
		return allow.toString();
	}

	/**
	 * Set the regular expression used to test for user who deployment is allowed.
	 *
	 * @param allow The new allow expression
	 */
	public void setAllow(String allow) {
		if (allow == null || allow.length() == 0) {
			this.allow = null;
		} else {
			this.allow = Pattern.compile(allow);
		}
	}

	/**
	 * Return the regular expression used to test for user who deployment is denied.
	 */
	public String getDeny() {
		if (deny == null) return null;
		return deny.toString();
	}

	/**
	 * Set the regular expression used to test for user who deployment is denied.
	 *
	 * @param deny The new deny expression
	 */
	public void setDeny(String deny) {
		if (deny == null || deny.length() == 0) {
			this.deny = null;
		} else {
			this.deny = Pattern.compile(deny);
		}
	}

	// --------------------------------------------------------- Public Methods

	/**
	 * Process the START event for an associated Host.
	 *
	 * @param event The lifecycle event that has occurred
	 */
	@Override
	public void lifecycleEvent(LifecycleEvent event) {

		// Identify the host we are associated with
		try {
			host = (Host) event.getLifecycle();
		} catch (ClassCastException e) {
			log.error(sm.getString("hostConfig.cce", event.getLifecycle()), e);
			return;
		}

		// Process the event that has occurred
		if (event.getType().equals(Lifecycle.START_EVENT))
			start();
		else if (event.getType().equals(Lifecycle.STOP_EVENT))
			stop();

	}


	// -------------------------------------------------------- Private Methods

	/**
	 * Deploy a web application for any user who has a web application present
	 * in a directory with a specified name within their home directory.
	 */
	private void deploy() {

		if (host.getLogger().isDebugEnabled())
			host.getLogger().debug(sm.getString("userConfig.deploying"));

		// Load the user database object for this host
		UserDatabase database = null;
		try {
			Class<?> clazz = Class.forName(userClass);
			database = (UserDatabase) clazz.newInstance();
			database.setUserConfig(this);
		} catch (Exception e) {
			host.getLogger().error(sm.getString("userConfig.database"), e);
			return;
		}

		ExecutorService executor = host.getStartStopExecutor();
		List<Future<?>> results = new ArrayList<Future<?>>();

		// Deploy the web application (if any) for each defined user
		Enumeration<String> users = database.getUsers();
		while (users.hasMoreElements()) {
			String user = users.nextElement();
			if (!isDeployAllowed(user)) continue;
			String home = database.getHome(user);
			results.add(executor.submit(new DeployUserDirectory(this, user, home)));
		}

		for (Future<?> result : results) {
			try {
				result.get();
			} catch (Exception e) {
				host.getLogger().error(sm.getString("userConfig.deploy.threaded.error"), e);
			}
		}
	}

	/**
	 * Deploy a web application for the specified user if they have such an
	 * application in the defined directory within their home directory.
	 *
	 * @param user Username owning the application to be deployed
	 * @param home Home directory of this user
	 */
	private void deploy(String user, String home) {

		// Does this user have a web application to be deployed?
		String contextPath = "/~" + user;
		if (host.findChild(contextPath) != null)
			return;
		File app = new File(home, directoryName);
		if (!app.exists() || !app.isDirectory())
			return;
	    /*
        File dd = new File(app, "/WEB-INF/web.xml");
        if (!dd.exists() || !dd.isFile() || !dd.canRead())
            return;
        */
		host.getLogger().info(sm.getString("userConfig.deploy", user));

		// Deploy the web application for this user
		try {
			Class<?> clazz = Class.forName(contextClass);
			Context context =
					(Context) clazz.newInstance();
			context.setPath(contextPath);
			context.setDocBase(app.toString());
			clazz = Class.forName(configClass);
			LifecycleListener listener =
					(LifecycleListener) clazz.newInstance();
			context.addLifecycleListener(listener);
			host.addChild(context);
		} catch (Exception e) {
			host.getLogger().error(sm.getString("userConfig.error", user), e);
		}

	}

	/**
	 * Process a "start" event for this Host.
	 */
	private void start() {

		if (host.getLogger().isDebugEnabled())
			host.getLogger().debug(sm.getString("userConfig.start"));

		deploy();

	}

	/**
	 * Process a "stop" event for this Host.
	 */
	private void stop() {

		if (host.getLogger().isDebugEnabled())
			host.getLogger().debug(sm.getString("userConfig.stop"));

	}

	/**
	 * Test allow and deny rules for the provided user.
	 *
	 * @return <code>true</code> if this user is allowed to deploy,
	 * <code>false</code> otherwise
	 */
	private boolean isDeployAllowed(String user) {
		if (deny != null && deny.matcher(user).matches()) {
			return false;
		}
		if (allow != null) {
			if (allow.matcher(user).matches()) {
				return true;
			} else {
				return false;
			}
		}
		return true;
	}

	private static class DeployUserDirectory implements Runnable {

		private UserConfig config;
		private String user;
		private String home;

		public DeployUserDirectory(UserConfig config, String user, String home) {
			this.config = config;
			this.user = user;
			this.home = home;
		}

		@Override
		public void run() {
			config.deploy(user, home);
		}
	}

}
